Today, printing presses are often controlled and monitored by a control station comprising a personal computer and various peripheral devices for a user to transmit control commands and monitor the operation of the printing press. The user is capable of monitoring and controlling a wide variety of operational parameters of the printing press through the computer and its programs. These monitoring and control functions are generally available through a menu-driven application program which allows the user to select desired operations at a level above the operating system of the computer.
However, the computer, also referred to herein as the control station computer of the printing press, should be capable of more than merely processing control signals and print status information. In accordance with the general aims of the printing industry today, the computer should be used to the fullest extent during the entire production process from the preliminary stages of printing to the final processing of the printed product. This idea is described in "Deutscher Drucker" in "Neue Leitstandtechnik im Zeitungsdruck" at page w140, No. 30, published Sep. 24, 1987 or in "Die Intelligente Druckmaschine--demonstriert am Beispiel einer Leitstandtechnik fur die Zukunft," page w2, No. 11, published Mar. 21, 1991. In addition, DE 3 829 341 A1 describes the use of control station technology in a network configuration in a printing facility.
It is also known from the above mentioned publications, "Neue Leitstandtechnik im Zeitungsdruck" and DE 3 829 341 A1 for a printing press control station to include a keyboard and video display device for enabling a user to input data and commands and to monitor the status of the printing device. As is known, these components are usually incorporated in a color matching consul associated with the printing press.
The primary information processing component of the printer control station is the computer, which is typically a microprocessor based personal computer having certain modifications to its exterior to withstand the operating conditions to which it is exposed in the printing environment.
In accordance with the network concept, it is known that the control station computer is connected via buses and interface components to the printing press, peripheral devices, and other networked computers. In particular the computer is typically connected to a control station video display device to enable the operator to monitor and control the operation of the printing press. The control commands are entered by the operator via the keyboard. These control operations are advantageously performed by a menu-driven application program executed by the control computer under the direction of the operator. The control operations provided by the menu driven interface are typically stored on permanent, non-volatile memory, which is typically a hard disk drive (though the non-volatile memory of the personal computer also includes ROM), and transferred to the volatile random access memory (RAM) during either start-up of the menu-driven program, or any other suitable time such as when the operator specifies a particular command listed on the menu.
The menu-driven user interface provides several advantages. The menu driven interface enables a user with limited knowledge of the control computer's operating system to control the printer by means of the displayed menu options. A further advantage of menu driven control is to avoid the necessity of an operator to access the operating system procedures of the control computer thereby providing protection from inadvertent or unauthorized access to computer facilities to which only a select group of technicians need access. The term "facilities" as used herein refers to all the hardware and software contained within the control station computer and any associated peripheral devices.
The control station typically contains at least one floppy disk drive or other suitable interchangeable mass memory storage means to enable transfer of new programs and data onto a hard disk drive or the RAM. By means of example, the loading of new programs and data into the hard disk drive associated with the control station computer occurs during initial installation of the control station, regular maintenance work, upgrading an old menu driven system, or installation of new features. These software loading tasks are not typically completed by the operator of the control station who performs his duties by means of the options provided by the menu driven printer control interface. Instead, the installation of new software is completed by a select group of highly-qualified technicians who are members of the computer development and maintenance staff.
The use of the typical Disk Operating System (DOS) based personal computer provides significant cost advantages over specially designed control station computers. First, the personal computer enjoys great hardware cost advantages due to the economy of scale and widespread competition which is typical of the personal computer. Therefore, the cost of the computer itself is relatively low. Second, because of the widespread use of the Intel based processors in personal computers, software packages are relatively inexpensive and knowledgeable programmers are relatively plentiful. Third, there is of course no need to develop an operating system for the control station computer. In general, the computer hardware and basic support software is relatively inexpensive for a personal computer based control station in comparison to a computer designed specifically for controlling a printing press.
Furthermore, the floppy disks associated with personal computer based systems are relatively inexpensive, easy to handle and easy to store.
The lack of security is however a significant disadvantage resulting from the use of a DOS based computer in a print control station. Even though the menu driven print control station program may be automatically executed during start-up of a control station computer through proper programming of an automatically executed batch file (autoexec.bat) stored on the hard drive of the computer, the operator may circumvent the execution of this autoexec.bat file by any of several known means. One known method is to terminate the execution of the autoexec.bat file by pressing the "control" and "c" keys simultaneously on the keyboard during start-up of the computer. This method of breaching the security of the computer has been eliminated by removing this key combination from the keyboard of the print control station.
The operator may also by-pass the execution of the autoexec.bat file stored on the hard drive by placing a floppy disk having a bootable sector, operating system software, and an alternative autoexec.bat file in the floppy disk drive prior to start-up of the computer. In such cases, the known Basic Input/Output System (BIOS) and DOS procedures will cause the personal computer to execute the autoexec.bat file on the floppy disk instead of the one stored on the hard disk drive. Therefore, merely removing certain key combinations from the keyboard and programming the autoexec.bat file on the hard drive of a personal computer to automatically execute a menu-driven application program provides no assurance that the operator will only invoke procedures provided by the menu-driven print control station program.
Once the operator has gained access to the commands and procedures of the operating system by means of a bootable floppy disk inserted into the floppy disk drive prior to start-up of the computer, the operator may invoke procedures which were not available to the operator through the menu-driven application program. The operator may delete, alter, or transfer existing files on the hard disk drive. The operator may add and execute new files thus preventing the proper operation of the printer control station. The control station in turn may provide improper printer status information to the operator or cause the control station computer to transmit erroneous control information to the printing press causing a malfunction of the printing station.
The floppy disk drive performs an integral role in the operation of the control station computer. Therefore, one may not solve the above security problem by removing the floppy disk drive. Nor is it a solution to prevent the reading of any floppy disk during start-up of the computer since there must remain a method for authorized persons to gain access to the operating system of the computer during upgrade and maintenance of the computer.
It is known to store passwords in non-volatile memory (the hard disk drive or the ROM), then query a user during start-up of the computer for a password in order to determine the level of access to be permitted the user to the computer's resources. The solution suffers from several disadvantages. Passwords can be forgotten and therefore a retrievable copy of the password may be necessary. Of course, the retrievable copy must be placed in a safe location to prevent others from seeing the password. The password may be seen or heard by another who may then use the password to gain access under the authority granted to the proper user.